1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel that can operate at high speed and can supply a uniform driving signal voltage.
2. Discussion of Related Art
A plasma display panel includes a discharge cell formed between a rear substrate in which barrier ribs are formed and a front substrate opposite to the rear substrate. In the plasma display panel, vacuum ultraviolet rays generated when an inert gas within each discharge cell is discharged with a high frequency voltage excite phosphors, thus implementing images.
FIG. 1 is a view illustrating the arrangement of electrodes of a general plasma display panel. The related art will be described with reference to FIG. 1.
Referring to In FIG. 1, scan electrode lines Y1 to Yn and sustain electrode lines Z1 to Zn are parallel to each other. Address electrode lines X1 to Xn (data electrode lines) cross the scan/sustain electrode lines. Each of discharge cells 1 is formed at a point where the electrodes cross one another.
A scan pulse is supplied through the scan electrode lines Y1 to Yn during the address period, so that the discharge cells 1 are scanned on a line basis. During the sustain period, a sustain pulse is supplied, so that a discharge is sustained in the discharge cells 1.
The sustain pulse is commonly supplied through the sustain electrode lines Z1 to Zn during the sustain period. Therefore, a discharge is sustained in the discharge cell 1 along with the scan electrode lines Y1 to Yn.
Furthermore, a data pulse is supplied on a line basis in synchronization with the scan pulse through the address electrode lines X1 to Xn during the address period. Therefore, the discharge cell 1 in which a discharge will be sustained is selected.
The scan/sustain/address electrode lines Y/Z/X are connected to drivers that supply the driving pulses. The drivers are generally formed on a printed circuit board (not shown) disposed on a rear surface of the plasma display panel. The drivers are connected to a pad unit of the electrodes formed at one side of the plasma display panel by means of a Flexible Print Cable (FPC), a Flat Flexible Cable (FFC) or the like.
FIG. 2 is a view illustrating a scan method of the plasma display panel. FIG. 2a is a view illustrating a single scan method and FIG. 2b is a view illustrating a dual scan method.
In the single scan method as shown in FIG. 2a, while an electrode line is selected by sequentially applying the scan pulse to lines from the first line to the last line of the scan electrode, one of the discharge cells 1 of the selected line, which will be discharged, is selected by applying the data pulse to the address electrode in synchronization with the scan pulse.
That is, assuming that scanning begins from the top right end of the plasma display panel 7, the scan driver 3 sequentially supplies the scan pulse beginning from the first scan electrode line Y1 and the data driver 2 supplies the data pulse, so that data are supplied to the discharge cell of a first discharge cell line 6.
Thereafter, data are supplied to the discharge cell on a second discharge cell line by means of the data pulse supplied to the address electrode lines X1 to Xn and the scan pulse supplied to the second scan electrode line Y2.
In the same manner, during the address period, lines from the first discharge cell line to an Nth discharge cell line are sequentially selected and data are then supplied to the selected lines.
On the other hand, the dual scan method is a method of performing scanning by bisecting a central portion of the plasma display panel as shown in FIG. 2b. Scan lines from a first scan line Y1 to a (n/2)th scan line (Yn/2) are supplied with data pulses in synchronization with scan pulses that are sequentially supplied from a first data driver 4. Scan lines from a ((n+1)/2)th scan line Y(n/2+1) to a nth scan line Yn are supplied with signals in synchronization with scan pulses that are sequentially supplied from a second data driver 5.
That is, in the dual scan method, the first half part and the second half part of the plasma display panel are scanned at the same time by means of a scan driver 3 during the address period. Therefore, the address period can be reduced approximately by half in comparison with the single scan method of the same resolution. Therefore, the dual scan method is advantageous in that the sustain period can be relatively extended and the display quality can be improved.
Meanwhile, the electrode lines X, Y and Z formed in the plasma display panel 7 has a high resistance value. Therefore, when a large-scale screen panel is driven, a relatively low voltage driving signal is applied to a discharge cell close to each of the drivers 2 to 5 due to voltage drop, and a relatively high voltage driving signal is applied to a discharge cell, which is far away from each of the drivers 2 to 5. Therefore, a relatively low voltage driving signal is supplied to the driver 2 and a discharge cell due to voltage drop.
That is, in the related art single scan method, a uniform driving signal (driving voltage) cannot be supplied to the entire discharge cells within the plasma display panel. As a result, a problem arises because the picture quality becomes uneven every panel region.
To solve this problem, the dual scan method has been used as shown in FIG. 2b. However, as a large-scale screen panel of 50 inch or more emerges, the problem in the single scan method remains intact. Furthermore, in the dual scan method, although the data drivers 4, 5 are respectively disposed at the top and bottom of the plasma display panel 7, voltage drop is generated at the center, which is far away from each driver, if the size of the plasma display panel becomes great. This results in variations in a driving signal.